Technical Field
The present invention relates to a camera and its manufacturing method, and more specifically to an on-board camera and its manufacturing method.
Description of Related Art
Waterproofness and focusing are two major issues of on-board cameras. The method for making on-board camera generally includes dispensing type, extrusion type and ultrasonic welding type.
1. Dispensing Method
Disadvantages: (1). Glue fills the space between the lens and the housing body: During production, it is difficult to ensure the accuracy of optical axis and focal length, and frequently changing temperature and humidity affects the performance of glue in long-term use, as a result optical axis, focal length and waterproof property cannot be guaranteed; (2). A relatively high amount of glue is being used, requiring certain time period curing, therefore such method is not suitable for production line and results in poor efficiency. There is no guarantee that the space between housing body and the lens is being filled in every unit during mass production resulting in high defect rate.
2. Extrusion Method
As shown in FIG. 1, the product uses a compression rubber cushion to achieve waterproofness: The rear housing 5 and the front housing 4 connects to the compression gasket 2 via screws 1 to achieve waterproofness of the rear housing and the front housing. The rear housing 5 presses on the inner housing 6, the inner housing 6 presses on the lens 3, and the lens 3 and the front housing 4 press on the O-shaped ring 7 to achieve waterproofness of the front housing 4 and the lens 3. The product uses focal length setting mode: The sensor 8 is fixed to the inner housing 6, the lens 3 and the inner housing 6 are adjusted up and down through screw threads.
Disadvantages: (1) The compression gasket 2 is prone to deformation during assembly, leading to waterproof failure; (2) when the rear housing 5 presses the inner housing 6 downwards, the inner housing 6 deforms under stress, causing the relative distance between PCBA and lens (focal length) to change (out of focus), resulting in blurry imagery, poor stability and high defect rate seriously affect product quality; (3). the torque between the lens 3 and the inner housing 6 is difficult to control, resulting in debris being generated during production and dark spots on the image.
3. Ultrasonic Welding Method
As shown in FIG. 2, the sensor 12 is integrally attached to the front housing lens 13 via screws, and the rear housing 11 is integrally welded with the front housing lens 13 by ultrasonic means.
Disadvantages: (1). The integrated structure of the sensor 12 and the front housing lens 13 leads to failure to focus adjustment, and defect rate of focal length caused by part tolerance is high; (2). Since the integrated ultrasonic welding of the rear housing 11 and the front housing lens 13 is achieved by welding two parts through mechanical vibration to heat and melt plastic parts, the vibration may damage the electronic elements on the sensor 12.